After 34 years of open hostility, the United States and Iran appear to be on the verge of a historic thaw. Iran's new reform-minded President Hassan Rouhani wrote in a Washington Post op-ed this past week that he wants to move, quote, "beyond impasses, whether in relation to Syria, my country's nuclear program or its relations with the United States." President Rouhani is scheduled to address the U. N. General Assembly on Tuesday, just a few hours after President Obama does the same.

Trita Parsi is the founder and president of the National Iranian American Council. He joins us from Los Angeles. Thanks so much for being with us.

TRITA PARSI: Thank you for having me.

MARTIN: This is not the first time that there has been talk of some kind of thaw in this difficult relationship between the U. S. and Iran. What makes this time different?

PARSI: You're quite correct. There's been a very tortured history and neither side has ever missed an opportunity to miss an opportunity. But the reason why this time may actually be one of the best opportunities so far is because not only is there now willingness on the Iranian side to move forward - and I think there's very intense media campaign by the Iranians that's quite sincere - there's also willingness on the American side. I'm very much convinced that Obama would like to resolve this issue.

But now on the Iranian side, there's also a president that seems capable of delivering. In the sense that even though he is somewhat reform-oriented, he is a centrist. And he has pretty strong relations with most elements of power in the Iranian political system and has a track record of delivering in the past when he was a national security advisor.

MARTIN: So, what is driving this change in tone and rhetoric, at least at this point?

PARSI: I think there're several different factors. One, is that Rouhani knows that the current degree of flexibility that he has is a very temporary one. Because if he cannot prove that his approach - his diplomatic and softer approach - pays more dividends for Iran than Ahmadinejad's theatrics, then the flexibility that he currently enjoys is going to be lost in a couple of months time.

I think that's part of the reason why the media campaign from the Iranian side is so intense. They sense that they have got a break from the hard-line position of the Supreme Leader as a result of the elections. But they have to prove that this other approach is effective. If they can't do it quickly, they will lose the opportunity.

MARTIN: How much of this is about getting relief from U. S. sanctions?

PARSI: Getting relief from U. S. is a very, very important factor. But I think it would be a mistake to believe that that's the reason, or the only reason why there is a stronger desire for it on the Iranian side right now. If you actually take a look at the people who are in power now, it's the same team that 10 years ago sent proposals to the United States for a grand bargain; 10 years ago, collaborated with the United States in Afghanistan.

This is a team that has a different worldview and a different belief system and has now gotten a second chance to pursue that reproach. Last time around, when they pursued it, the West did not respond. This time around, we will see if the United States will meet the Iranians halfway.

MARTIN: Trita Parsi is the founder and president of the National Iranian American Council. He spoke to us from Los Angeles. Thanks so much for speaking with us, Mr. Parsi.